1. Field of the Invention
The present invention relates to an information search field, and more particularly to a search keyword improvement apparatus, server and method, which enable appropriately narrowed information to be searched for by expanding a keyword input by a user for information search.
2. Description of the Related Art
As a technique of performing information search by a simple operation, there is known a technique of acquiring an auxiliary keyword from a co-occurrence ratio keyword database, based on a keyword designated by a user, and performing a search using the designated keyword and auxiliary keyword (see, for example, JP-A 2006-79366 (KOKAI)).
Since in the conventional technique, defined keywords are not updated, an accurate search result may not be acquired when, for example, the property of documents as search targets is changed or new documents appear.